Here's something else you might want to consider.
The last time I did a medical and had a discussion about aged pilots, the doctor told me that in old people the guy could be doing a crossword on Monday and be non compos mentis by Friday.
He mentioned a similar problem with doctors, how does anyone know a doctor is past retirement, should have given it up but hangs in there and starts prescribing the incorrect medicines.
Bet you've read about that before.